Igniting device

ABSTRACT

A device for actuating a propellant charge of a launched projectile wherein a member moves in response to positive and/or negative acceleration of the projectile to actuate the propellant charge or to actuate a delaying means and obtain, at a preselected time thereafter, setting off of the propellant charge.

United States Patent Inventor George II. Hoprneier Rochester, Mich. Appl. No. 798,330 Filed Feb. .1 1, 1969 Patented Oct. 12, 1971 Assignee LIV Aerospace Corporation Dallas, Tex.

IGNI'IING DEVICE 5 Claims, 6 Drawing Figs.

US. Cl. 102/75, 1021?] Int. Cl. F42c 15/04, F42c 15/24, F420 15/34 Field 01 Search. 102/70, 71,

References Cited UNITED STATES PATENTS Catlin Granath et al..... Hjelm Lee et al. Noles Primary ExaminerBenjamin A. Borchelt Assistant Examiner-Thomas H. Webb Attorney-H. C. Goldwire ABSTRACT: A device for actuating a propellant charge of a launched projectile wherein a member moves in response to positive and/or negative acceleration of the projectile to actuate the propellant charge or to actuate a delaying means and obtain, at a preselected time thereafter, setting ofi of the propellant charge.

- IGNI'I'ING DEVICE ,This invention relates to ammunition and explosive devices and, more particularly, to an improved igniting device for propellant charge for aprojectile.

Modem projectiles are often designed to obtain additional thrust by the combustion of a projectile-contained, secondary propellant charge. It has also been found advantageous to ignitethis secondary propellant charge at one or another of several positions on the projectile's flight path. By so utilizing a primary or charge to propel the projectile from its resting position and, at a preselected time thereafter, impartingadditional thrust to the projectile, projectiles can be designed to follow an infinite number of flight path configurations. Projectiles of this type are generally launched either by gunboosting the projectile or by combusting a projectile-contained, first-stage, propellant charge. In the gun-boosting method, the projectile is placed in a gun barrel in adjacency to aseparate propellant charge. Expansion of gases during combustion of the initial charge propels the projectile from the gun barrel, and igniting means within the projectile thereafter ignite the secondary propellant charge. In the other, common launching method, the primary charge is an integral part of the projectile. This projectile is either free-launched or tubelaunched by combusting the projectile-contained, first-stage propellant charge. The emission of gases from the rearward end of the projectile propels the projectile from its resting position, and igniting means within the projectile thereafter ignitethe secondary propellant charge.

Regardless of the launching method employed, relatively high velocities are obtained during the first portion of the projectiles flight path. Frictional and other forces constantly produce a reduction of projectile velocity which, combined with the effects of gravitational forces, is accompanied by alterations of the projectile attitude and flight path. Properly igniting the secondary propellant charge at an exact, preselected instant during a time within which these alterations occur thus becomes a critical problem in designing a projectile which will follow a predictable flight path.

The mechanical devices heretofore employed for ignition of the secondary charges of missiles of this type are generally of complex construction and operation, require costly, manual assembly, and are notoriously unreliable. While they have proven slightly more reliable than previously used mechanical devices, electrical initiating devices are disadvantageous in that they tend to be fragile, possess hazardous handling characteristics, and need electrical power sources.

These ignition problems become increasingly acute as ignitiomdelay devices are incorporated. Most time-delay devices are pyrotechnic trains which, for proper operation, must combust at a stable rate which is rarely attained. Because of the extreme temperatures and severe shocks imposed on these devices during combustion of their primary charges, malfunctions of pyrotechnic devices are common. These failures are generally caused not only by erratic burning or impact destruction of the delay train by inertial forces during primary acceleration, but also by other factors including high-temperature preignition of the secondary charge. Prior time-delay devices of other than pyrotechnic nature have commonly employed motors, clockworks or the like, relatively complicated linkages, and other complexities which tend to make them both expensivev and of less than satisfactory reliability. I

Because of the complex construction of the previously used ignition and timing devices, they generally are bulky, require comparatively large housings, have sometimes numerous moving parts which may malfunction, and are relatively difficult to install and adjust properly. Considering the problems of construction and operation experiences with presently used igniter and timing devices it becomes evident that, the flight paths of supposedly identical projectiles may vary greatly. Effective, predictable projectile operation therefore substantially depends on reproducible timing of ignition of the secondary propellant charge.

It is, accordingly, an object of this invention to provide means yielding improved accuracy of control over the time of ignition of the secondary propellant charge of a projectile.

Another object is to provide means of the above character, which means is of improved reliability.

Yet another object is to provide a device for setting off the percussion igniter for the secondary propulsive charge of a projectile, which device has safe handling characteristics.

A still further object is to provide a device of above character and of a sturdy construction which employs few moving parts.

Still another object is to provide such adevice which is relatively small and compact and which is well adapted to functioning in a small housing.

An additional object is to provide a device as characterized above, which device is simple and economical to construct.

Other objects and advantages will be apparent from the specification and claims and from the accompanying drawing illustrative of the invention. I

In the drawing:

FIG. I is a fragmentary, front view, partially in longitudinal section, of a projectile provided with the igniting device of the invention.

FIG. 2 is a similar view of a modification of the invention; v

FIG. 3 is a view of a portion of the modification of FIG. 2 in which the firing pin is shown in its rearward, latched position;

FIG. 4 is an enlarged view of the timing and triggering means of the modification shown in FIG. 2, portions of the housings thereof being cut away;

FIG. 5 is a view, similar to FIG. I, of another modification of the invention, and

FIG. 6 is an enlarged view of the timing and firing means of the modification shown in FIG. 5, portions of the housings thereof being cut away.

Referring to FIG. 1 a device 10 for setting off or actuating a percussion igniter 11 having a striking face 12 for a secondary propellant charge 14 of a gun-boosted projectile 16 or missile has a longitudinal axis (not shown) which is aligned along the forward direction of the projectile 16. A cylindrical housing 18 has a chamber 20, forward and rearward disc-shaped end members 22, 23, and narrow first and second middle members 24, 26. The forward end member 22 of thehousing I8 is at-, tached to a nozzle 28 which is connected to the rearward end 30 of the projectile l6. Grooves 32, for example, are formed on the forward end member 22 adjacent the nozzle 28 to facilitate prompt removal of the device 10 from the projectile 16 in response to forces exerted on the forward end member 22 upon initiation of combustion of the secondary propellant charge 14. Each housing member 22, 23, 24, 26 spans the chamber 20 substantially perpendicularly to the longitudinal axis (not shown) of the housing 18. The forward end member 22 has a hole 34 which is formed therethrough at substantially the center (not shown) of the member 22 and is adapted to hold, by frictional forces, a percussion igniter 11 which is in contact with the secondary propellant charge 14. Appropriate locking means (not shown) may be used to maintain the igniter 11 in the hole 34. An igniting shield 37 having a biasing means 39 is in contact with and covers the igniter striking face 12.

The first and second middle members 24, 26 each have an opening formed therethrough at substantially the enter of the respective member, through which openings a firing pin 36 having first and second ends 38, 40 extends for movably and slidably mounting the same on the middle members 24, 26 and for movement, along the longitudinal axis (not shown) of the projectile 16 between a first or forward position, (shown) and a second or rearward position. At its forward position, the first end 38 of the pin 36 is in contact with the igniter striking face 12. At its rearward position, the first end 38 of the pin 36 is rearwardly spaced from the igniter II and is located, for example, in register with the point 42. Intermediate its two ends 38, 40 the pin 36 has a laterally extendin'g portion such as a disc-shaped flange 44 or collar which is rearwardly spaced from the housing first middle member 24 in all positions of the pm.

A resilient means 46 urges the pin 36 to its first or forward position (shown) and is capable of being deflected during and by motion of the pin 36 from the pins first to its second or rearward position. In the embodiment shown, the resilient means 46 is a coiled spring 46 through which the pin 36 extends, the spring 46 being footed at one of its ends against the rearward housing second middle member 26 and, at its other end, against the flange 44 of the pin 36. The spring 46 is in compression between the housing second middle member 26 and the pin flange 44.

An ignition shield 37 having a planar surface with dimensions larger than the igniter striking face 12 may be inserted, for safety purposes, between the igniter striking face 12 and the pin fist end 38 prior to ignition of the primary propellant charge when the pin is in its first position. A biasing means 39, such as a coiled spring, has one end connected to the ignition shield 37 and the other end connected to an inner wall of the housing 18. With the ignition shield 37 in contact with the igniter striking face 12 and pin first end 38, the biasing means 39 is in tension.

FIG. 2 shows a device for a gun-launched or multistage projectile 16 which is subject to forward propulsion by an initial charge (not shown) and, at a predetermined time after initial charge acceleration, to further forward acceleration by a subsequent charge 14. In this embodiment of the invention, the projectile 16, secondary propellant charge 14, housing 18, noale 28, percussion igniter 11, resilient means 46 and firing pin 36 are essentially the same as previously described in reference to Flg. 1. In addition, a detaining means 48 is pivotally mounted on the first middle member 24 at a location spaced from the housings longitudinal axis (not shown) for movement between first (shown) and second (broken lines) positions. The detaining means, for example, is an angular arm 48 which has first and second portions 50, 52. The first portion 50 of the arm 48 extends from its pivot point 54 inwardly toward the longitudinal axis (not shown) of the housing 18, and, in its first position (shown), terminates at a location adjacent and inwardly spaced from the periphery of the pins flange 44. When the pin 36 is in its first position (shown), the flange 44 is located forwardly of the arm first portion 50. A timing means 56 and a triggering means 58 are attached to the inner surface of the wall 60 of the housing 18 at a location forwardly spaced form the housing first middle member 24 and adjacent the second portion 52 of the arm 48, the timing means 56 and triggering means 58 being disposed between the housing wall 60 and the arm second portion 52. Biasing means 62 such as a tension spring 62 is attached between the housing wall 60 and the arm second portion 52 and urges the second portion 52 of the arm 48 toward its first position (shown), in which position the ann 48 is in contact with the timing 56 and triggering means 58.

In the second position of the arm first portion 52, the distal end 64 of the ann second portion 50 rides on the periphery of the flange 44.

Referring to FIG. 3, the timing means 56, triggering means 58, arm 48, and pin 36, previously described with reference to FIG. 2, are shown with the pin 36 in its second position and the arm 48 in its first position. When the pin 36 is in its second position (shown), its flange 44 is located rearwardly of the first portion 50 of the arm 48 and a foot 66 located on the rearward surface of the arm first portion 50 is in contact with the forward surface of the flange 44 and holds the pin 36 at its second position (shown).

Referring to FIG. 4, which shows in more detail the timing means 56 and triggering means 58 previously described with reference to FIG. 2, a rigid triggering bar 68 having a first endportion 70 adjacent one wall 72 of the triggering means housing 74, a second end-portion 76 extending from that housing through an opening 78 therein and in contact with the arm second portion 52, and an enlarged-diameter middle portion 80 which has a circumferential notch or groove 82 formed therein is slidably mounted within the housing 74 by and in contact with a plurality of guiding rings 84 rigidly attached to the inner walls of the housing 74 for movement from a first position (shown) to a second position (to be described). In the first position of the bar 68, the first end-portion 70 is adjacent one wall 72 of the housing 74 and the second end-portion 76 is in contact with the arm second portion 52 when the arm 48 is in its first portion (shown). In the second position (not shown) of the bar 68, its first end-portion 70 is spaced from the wall 72 of the housing 74 and its second end-portion 76 is in contact with the arm second portion 52 and the arm 48 is in its second position (not shown).

A coiled spring 86, through which the first portion 70 of the bar 68 extends, is footed at one of its ends against the bar middle portion and, at its other end, against an inner surface of the wall 72 of the triggering means housing 74. In the first position of triggering bar 68 (shown), the spring 86 is in compression between the triggering means housing 74 and the bar middle portion 80; in the second position (not shown) of the triggering bar 68, the spring is substantially expanded.

The timing means 56 is of any desired, conventional type which has an output shaft 89 that remains motionless during a preselected time and thereafter rotates for actuation of an associated member 88. The shaft 89 is provided with a driving gear 88 which is mounted within the timing means housing 98 and spaced forwardly from and in register, laterally of the bar 68, with the triggering bar groove 82. A detaining means comprising a rigid, elongated member 90 having a toothed endportion 92 in register with and engaging the timing gear 88, a smooth, opposite end-portion 94 extendible into the triggering bar groove 82 when the bar 68 is in its first position (shown), and a smooth middle portion 96 extending from the timing means housing 98 into the triggering-means housing 74 through openings in the respective housings is mounted by and in contact with a plurality of guiding rings 84 rigidly attached to the triggering and timing means housings 74, 98 and allowing sliding movement of the detaining member 90 therethrough from a first position (shown) to a second position (to be described). In the first position of the detaining means 90, its smooth end-portion 94 is positioned within the triggering bar groove 82; in the second position of the detaining means 90, its smooth end-portion 94 is outside the triggering bar groove 82.

Referring to FIG. 5, another embodiment of this invention is shown which is particularly adapted for controlled ignition of a secondary propulsive charge 14 of a multistage projectile 16 at a predetermined time after burnout of the initial charge (not shown). The projectile 16, secondary propellant charge 14, housing 18, nozzle 28, percussion igniter II and resilient means 46 of this embodiment are essentially the same as previously described with reference to FIG. 1. In addition, a timing means 56 having a housing 98 and a switch 100 is mounted on the forward surface of the first middle member 24 in coaxial relation to the longitudinal axis (not shown) of the projectile 16. The switch 100 extends through an appropriate opening (not shown) in first member 24 and terminates at a location spaced rearwardly of the middle member and adjacent an actuator 102. The actuator 102 is essentially the same as the firing pin 36 described in reference to FIG. 2, with the exceptions that a first end 104 of the actuator 102 is preferably more blunt and shorter than the first end 38 of the pin 36 of FIG. 2.

A firing means 106 having a housing 108 and an igniting pin 110 is rigidly mounted on the forward surface of the timing means housing 98 and in coaxial relation to the longitudinal axis (not shown) of the projectile 16. The igniting pin 110 has a distal end. 1 12 which, when the pin 1 10 is in its first position (shown), is spaced form and in proximity to the striking face 12 of the percussion igniter 11.

Referring to FIG. 6, which shows in more detail the timing and firing means 56, 106 previously described with reference to FIG. 5, a rigid igniting pin 110 having a longitudinal axis (not shown), a first end-portion 114 adjacent one wall 116 of the firing means housing 108, a second end-portion 118 extending from that housing through an opening 120 therein, and an enlarged-diameter middle portion 122 which has a forward end 124 substantially perpendicular to the longitudinal axis (not shown) is slidably mounted within the housing 108 by and in contact with a plurality of guiding rings 84 rigidly attached to the inner walls of the housing 108 for movement from 'a first position (shown) to a second position (to be described). In the first position of the igniting pin 110, the first end=portion 114 is adjacent one wall 116 of the housing 108 and the second end-portion 118 is adjacent the igniter striking face 12. In the second position of the igniting pin 110, the first end-portion 114 is spaced from the wall 116 of the housing 108 and the second endportion 118 is in contact with the igniter striking face 12.

- A coiled spring 126, through which the first portion 114 of the igniting pin 110 extends, is footed at one of its ends against the pin middle portion 122 and, at its other end, against an inner-surface of the wall 116 of the firing means housing 108. Irithe fist position of the igniting pin 110 (shown), the spring 126 is in compression between the firing means housing 108 and the pin second portion 122. In the second position of the igniting pin 110 (not shown) the spring 126 is substantially expanded.

A firing arm 128 having first and second portions 130, 132 is pivotally mounted for movement from a first (shown) to a second (not shown) position on the housing 1080f the firing means 106 at a location forwardly and laterally spaced from theforward end 124 of the middle portion 122 of the igniting pin *l-ltlwhen the igniting pin is in its first position (shown). In thefirst position of the firing arm 128 (shown), its first portion 130 is in contact with the forward end 124 of the igniting pin middle portion 122 and holds the pin 110 at its first position. lnthe second position (not shown) of the firing arm 128, the arm is laterally spaced from the igniting pin 1 10.

The timing means 56 is of any desired, conventional type which has an output shaft 89, that remains motionless during a preselected time and thereafter rotates for actuation of an associated member 88. The shaft 89 is provided with a driving gear 88 which is mounted within the timing means housing 98 and spaced rearwardly from the second portion 132 of the firing jarm 128. An actuating means: comprising a rigid, elongated actuating member 136, a force-transmitting means distinct from the actuator .102, having a toothed end-portion 138 in register with and engaging the timing gear 88, a smooth end-portion 140 in contact with the firing arm second portion 132, and a smooth middle portion 142 extending from the timing means housing 98 into the firing means housing 108 through openings in the respective housings (not shown) is mounted by and in contact with a plurality of guiding rings 84 rigidly attached to the firing and timing means housings and allowing 'sliding movement of the actuating member 136 therethrough from a first position (shown) to a second position (to be described). In the first position of the actuating member 136 its smooth end-portion 140 is positioned in contact with the firing arm second portion 132 and the arm 128 is in its first position (shown). In the second position (not shown) of the actuating member 136 its smooth end-portion 140 is in contact with the firing arm second portion 132 and the arm is in its second position (not shown).

In the operation of the device of this invention, a primary propellant charge (not shown) launches the projectile 16. That initial charge may be separate from the projectile 16, as in a gun-launched projectile, or an integral part of the projectile, such as the first stage of a tube-launched or free-launched multistage rocket.

During combustion of the primary propellant charge (not shown), the projectile 16 is launched into space. The maximum velocity of the projectile 16 in response to the primary propellant charge (not shown) is relatively high andis attained in arelatively short period of time; i.e., the projectile I6 is rapidly accelerated during combustion of the primary charge.

With reference to FIG. 1 described above as showing a device preferably used with gun-launched projectiles, a rearwardly directed inertial force is imposed on the pin 36 during acceleration of the projectile 16 in response to the primary propellant charge (not shown). The inertial force is greater than the forwardly directed force exerted on the pin 36 by the spring 46 and, during forward acceleration of the projectile 16, causes the pin to move from its first to its second position and thereby further compresses the spring. Where a shield 37 has been used and as the pin 36 moves toward its second position, the biasing means 39 removes the igniting shield 37 from the striking face 12.

As the projectile 16 leaves the barrel of the gun (not shown), the gases generated by combustion of the primary propellent charge (not shown) escape to the atmosphere and. acceleration of the projectile is sharply terminated. Correspondingly, the inertial force exerted by the rapidly 36 on the spring 56 is suddenly ended and the potential energy stored in the compressed spring is released. The pin 36, in response to the spring 46, moves rapidly to its first position and strikes and sets off the percussion igniter 11, which thereupon ignites the secondary propellant charge 14. The force rearwardly exerted on the device 10 by the combustion of the secondary propellant charge 14 breaks the forward end member 22 along its grooves 32 and removes the device from the projectile l6.

In gun-launched projectiles, it is preferred that the secondary propellant charge be ignited only at locationsoutside of the gun barrel. By so restricting the location for ignition of the secondary propellant charge, the gun barrel is not subjected to the increased pressure and corrosive products associated with combustion of the secondary propellant charge.

Since the device 10 functions to set off the-igniter 11 only'in response to the termination of acceleration of the projectile 16, it has extremely safe handling characteristics and the time of ignition of the secondary propellant chargel4 is accurately and reliably controlled. Because of the few moving parts and the limited movement of these parts, the device of this invention is sturdy, small, compact, adapted to function in a small housing, and simply and economically constructed.

In the operation of the embodiment shown in FIG. 2, the pin 36 is constructed to function in response to acceleration of the projectile 16, as previously described, with the exception that the percussion igniter 1 1 is actuated at a preselected time after initial acceleration of the projectile by the primary propellant charge 14. g

Rearward movement of the pin 36 toward the second position in response to the acceleration induced by the primary propellant charge causes the flange 44 to strike that ann first portion 50 and pivot the arm 48 to its second position. Movement of the arm second portion 52 to its second position releases and thereby actuates the timing means switch t00 and extends the biasing spring 62. .Upon the flange 44 continuing its rearward movement until it reaches a position rearwardly spaced from the arm first portion 50, the biasing spring 62 pivots the arm 48 back to its first position,whereupon the arm lies in the path of the flange and prevents forward movement of the pin 36 beyond its second position, shown in FIG. 3. Its switch 100 having been released, the timer begins a measuring of a preselected time interval.

With reference to FIG. 4, at a preselected time after acceleration of the projectile 16 has caused the pin 36 to move to its second position, the timing means 56 supplies a torque to the output shaft 89 and thereby rotates the gear 88 in a direction moving the detaining member 90 from its first position (shown) to its second, position in which the detaining smooth end means portion 94 is removed from the bar groove 82 and thus releases the triggering bar 68. In response to the force exerted on the triggering bar 68 by the spring 86, the triggering bar moves promptly to its second position and thereby forces the arm 58 to pivot to its second position, shown in broken line in FIG. 2, and releases the pin 36. The pin 36, in response to the forwardly directed force exerted on it by the compressed spring 46, moves rapidly to its first position and strikes and sets off the percussion igniter l 1, thereby igniting the secondary propellant charge 14. The rearward force exerted on the device 10 by combustion of the secondary propellant charge 14 breaks the forward end member 22 along the grooves 32 and removes the device 10 from the projectile 16. In projectiles using the device shown in FIG. 2, the ignition time of the secondary propellant charge 14 can be controlled to occur at a preselected time after a gun-launched projectile leaves the gun barrel or, in a multistage rocket, after burnout of the rocket primary propellant charge. Since the secondary charge ignition time is preselected, the projectile 16 reaches a desired height, distance, and attitude before ignition of the secondary propellant charge 14 and follows a flight path of preselected configuration.

The embodiment of the invention shown in FIG. is constructed to function in response to acceleration of the projectile 16, as previously described with reference to FIG. 2, except that the pin 36 of FIG. 2 is replaced with an actuator 102. Upon decrease of the projectiles acceleration, the actuator 102 moves forwardly to its first position, engages and depresses the switch 100, and actuates the timing means 56. Its switch 100 having been released and depressed, the time 56 begins a measuring of a preselected time interval.

Referring to FIG. 6, at a preselected time after its actuation (and as described previously in connection with FIG. 4), the timing means 56 rotates the driving gear 88, thus moving forwardly the actuating member 136. This motion of the actuating member 136 forces the firing arm 128 to pivot to its second position, in which position the arm first portion 130 is removed from the pin middle portion 122, and thus releases the igniting pin 110. The igniting pin 110, in response to the forward force exerted by the compressed spring 126, moves rapidly to its second position and strikes and sets off the percussion igniter II and thereby ignites the secondary propellant charge 14. The force rearwardly exerted on the forward end member 22 (FIG. 5) by the secondary propellent charge 14 breaks that member along its grooves 32 and removes the device from the projectile 16.

The embodiment of the invention shown in FIG. 5 accurately aNd reliably controls the secondary propellant charge ignition time of a multistage rocket having gradual deceleration rates.

While only one embodiment of the invention, together with modifications thereof, has been described in detail herein and shown in the accompanying drawing, it will be evident that various further modifications are possible in the arrangement and construction of its components without departing from the scope of the invention.

What is claimed is:

1. For a multistage projectile having a longitudinal axis and a percussion igniter, the projectile being subject to forward acceleration by an initial propulsive charge and to further forward acceleration by a subsequent propulsive charge, a device for controlled ignition of the subsequent charge at a predetermined time after actuation of the initial charge, said device comprising:

a firing pin which has a first end and is movably mounted with relation to the projectile for movement along said longitudinal axis between a forward position wherein the first end of the pin is in contact with the percussion igniter and a rearward position wherein the first end of the pin is rearwardly spaced from the igniter, a firing pin being movable to its second position by inertial forces thereon during acceleration of the projectile by the primary propulsive charge;

resilient means urging the pin to the forward position with a force less than rearwardly directed inertial forces imposed on the resilient means by the firing pin during forward acceleration of the projectile by the primary propulsive charge, the resilient means having a portion contactable by said pin and displaceable by the inertial forces of the pin; detaining means responsive to movement of the pin to its rearward position for locking the pin in said rearward position and actuatable for releasing the pin to allow movement of the pin, by forces provided by the resilient means, to its forward position and into striking contact with the igniter; timing means actuated in response to movement of the firing pin from its forward position and toward its rearward position and operable for providing a signal at a preselected time thereafter; and a triggering means receptive and responsive to the signal provided by the timing means for actuating the detaining means, whereby the pin is released from its rearward position, travels forward and strikes the percussion igniter. 2. A device as set forth in claim I, wherein the detaining means comprises an arm.

3. A device as set forth in claim 1, wherein the detaining means comprises:

an arm pivotally mounted on the projectile in contact with the timing means, adjacent the triggering means, and positioned where it is contacted and moved relative to the timing means by the pin during rearward motion thereof induced by forward acceleration of the projectile, whereby movement of the arm actuates the timing means. 4. For a multistage projectile which has a longitudinal axis and a percussion igniter and which is subjected to forward acceleration by an initial propulsive charge and to further forward acceleration by a subsequent propulsive charge, a device for controlled ignition of the subsequent charge at a predetermined time after ignition of the initial charge, said device comprising:

an actuator which has a member portion movably mounted with relation to the projectile for movement along said longitudinal axis between a forward position and a rearward position and which further has resilient means urging the member portion to the forward position with a force less than inertial forces rearwardly imposed on the resilient means by the member portion during forward acceleration of the projectile by the primary propulsive charge; timing means having a force-transmitting means distinct from the aCtuator, said timing means being actuated by contact with the member portion during movement thereof from its rearward to its forward position and operable for providing a signal, supplied through said force-transmitting means to the firing means recited below, at a preselected time thereafter; and firing means receptive and responsive to the signal provided by the timing means through said force-transmitting means for striking of the percussion igniter. 5. A device as set forth in claim 4 wherein the firing means comprises:

an igniting pin movably mounted relative to the percussion igniter for movement from a first position wherein the igniting pin is spaced from the igniter to a second position wherein the igniting pin is in contact with the percussion igniter; resilient means urging the igniting pin to the second position; and means for holding the igniting pin in its first position and receptive and responsive to the signal provided by the force-transmitting means of the timing means for releasing the igniting pin. 

1. For a multistage projectile having a longitudinal axis and a percussion igniter, the projectile being subject to forward acceleration by an initial propulsive charge and to further forward acceleration by a subsequent propulsive charge, a device for controlled ignition of the subsequent charge at a predetermined time after actuation of the initial charge, said device comprising: a firing pin which has a first end and is movably mounted with relation to the projectile for movement along said longitudinal axis between a forward position wherein the first end of the pin is in contact with the percussion igniter and a rearward position wherein the first end of the pin is rearwardly spaced from the igniter, a firing pin being movable to its second position by inertial forces thereon during acceleration of the projectile by the primary propulsive charge; resilient means urging the pin to the forward position with a force less than rearwardly directed inertial forces imposed on the resilient means by the firing pin during forward acceleration of the projectile by the primary propulsive charge, the resilient means having a portion contactable by said pin and displaceable by the inertial forces of the pin; detaining means responsive to movement of the pin to its rearward position for locking the pin in said rearward position and actuatable for releasing the pin to allow movement of the pin, by forces provided by the resilient means, to its forward position and into striking contact with the igniter; timing means actuated in response to movement of the firing pin from its forward position and toward its rearward position and operable for providing a signal at a preselected time thereafter; and a triggering means receptive and responsive to the signal provided by the timing means for actuating the detaining means, whereby the pin is released from its rearward position, travels forward and strikes the percussion igniter.
 2. A device as set forth in claim 1, wherein the detaining means comprises an arm.
 3. A device as set forth in claim 1, wherein the detaining means comprises: an arm pivotally mounted on the projectile in contact with the timing means, adjacent the triggering means, and positioned where it is contacted and moved relative to the timing means by the pin during rearward motion thereof induced by forward acceleration of the projectile, whereby movement of the arm actuates the timing means.
 4. For a multistage projectile which has a longitudinal axis and a percussion igniter and which is subjected to forward acceleration by an initial propulsive charge and to further forward acceleration by a subsequent propulsive charge, a device for controlled ignition of the subsequent charge at a predetermined time after ignition of the initial charge, said device comprising: an actuator which has a Member portion movably mounted with relation to the projectile for movement along said longitudinal axis between a forward position and a rearward position and which further has resilient means urging the member portion to the forward position with a force less than inertial forces rearwardly imposed on the resilient means by the member portion during forward acceleration of the projectile by the primary propulsive charge; timing means having a force-transmitting means distinct from the aCtuator, said timing means being actuated by contact with the member portion during movement thereof from its rearward to its forward position and operable for providing a signal, supplied through said force-transmitting means to the firing means recited below, at a preselected time thereafter; and firing means receptive and responsive to the signal provided by the timing means through said force-transmitting means for striking of the percussion igniter.
 5. A device as set forth in claim 4 wherein the firing means comprises: an igniting pin movably mounted relative to the percussion igniter for movement from a first position wherein the igniting pin is spaced from the igniter to a second position wherein the igniting pin is in contact with the percussion igniter; resilient means urging the igniting pin to the second position; and means for holding the igniting pin in its first position and receptive and responsive to the signal provided by the force-transmitting means of the timing means for releasing the igniting pin. 